Internal combustion engine



Nov. 11, 1941.

R. M. NARDONE INTERNAL COMBUSTION ENGINE Filed Feb. 15, 1939 rm I! Q l I F I. ww m| Q \N \N, w

w h NN v. v mm. n .I Q, vm mm mw mm u R. R, A vv \\\\\\\\\\\\\\\\q\ INVENTOR. B Romeo M Nara/one A ORN Patented Nov. 11, 1941 means 1 Ilhi nela c etorinte a com ust en nes; and: nart c-ular s to the; start n the eof.

t s mmon. p act e, to emplo or s artin an internal combustion engine, aseparat-e unit (starter l embodying; ajrotatable part normally dis-engaged from, but shiftable ment with, one end of the engine crank-shaft, or some part rotatable therewith. Thus, in aircraft engines, for example, there is provided a. cylindrical (straight or tapered) flanged support,

into enage-' known as a "mounting flange to receive such a starting unit, and within the cylindrical support are two correspondingly cut clutch elements, one of which is an integral part of the engine proper and rotat'es at all times with the engine crank-shaft, while the other is an integral part of the starting unit, and is normally spaced a fraction of an inch to the rear of the engines clutch element. Upon energization of the starting unit the rotating start'er clutch element moves forwardand drivably engages the engines clutch element, to impart initial rotary movement to the engine crank-shaft. Concurrently fuel and igniting sparks are supplied to the combustion chambers of the engine, inproper sequence; starting thereby results, whereupon the engines clutch 'elementit is commonly called a jaw-overruns the starter jaw and the latter returns to its normal position of disengagement with respect to the rotating parts of the engine.

Prior to completion of the starting action the engines clutch element may repeatedly overrun the starter jaw, as immediately after passing a high compression point or under an isolated hazard by altering the engine proper, .rather than. the starter unit; and it is'accordingly an object of the invention to provide a methodl'of absorbing: the, effects of an engine back-fire 3 without any; change whateverinitheastructureon engine starting functioning of the 'normal mechanism.

Another object of the invention is to provide back-fire" absorbing means operativelyYassociated with the engine, but operatively dissociated from the normal engine starting parts.

5 Another object is to provide back-fire absorbing means adapted to fit within the usual cylindrical support to which the engine starter unit is attached, whereby the extent. of alteration of the engine assembly is reduced to a minimum.

These and other objects of the invention will become apparent from inspection of the following specification when read with reference to the accompanying drawing wherein is illustrated the preferred embodiment of the invention. It is V to be -expressly understood, however, that the drawing is for the purpose of illustration only, and is not designed as a definition of the limits of the invention, reference being had to the appended claim for this purpose.

In the drawing reference character 5 designates a rotatable part of an aircraft engine of the type having a supercharger casing 6 providing bearing surfaces 1 and 8 to rotatably firing impulse before the engine starts under its own power. These actions usually accelerate the engine much faster than the starter can follow; and before the resumption of the drive by the starter a back-fire, or premature explosion in one of the cylinders, may occur, causing a rocking back of the engine jaw member with exceptional violence against the starter jaw.

Heretofore various means have been provided to save the starter unitfrom damage due to the actions above described; but practically all such means involve changes in thestructure of the starter unit and also, in most instances, alter the mOde of operation and the efiiciency thereof in normal cranking-that is, on the more frequent occasions when there is no back-firing" of the engine, and hence no need for the extra complications of the starter construction. I

The present invention reflects a different concept, namely, that of meeting the back-fire support the crank-shaft drivem shaft 5, and also having a thickened section 9 presenting a plane annular surface concentric with shaft 5 and adapted to receive the tapered cylindrical support II which holds the starter unit 12 in position, the starter unit and the cylindrical support having registering flanges, as indicated at I3 and M, to receive the supporting bolts IS.

The starter jaw I1 is disposed at the forward end of the unit [2, within the cylindrical support II, and opposite the engine jaw 18 which, as shown, is integral with a socketed member or sleeve l9 which is positively connected to shaft 5 by suitable means 2|. The pins 2| also serve to retain spacer 22 and member 23 in place, the former being interposed between combined thrust and radial bearings 24, and the member 23 being the outer race of a uni-directional roller clutch whose inner race 26 extends back over bearings 24 and receives a friction disc assembly 25 adapted to absorb the energy of a reverse rotational impulse imparted to shaft 5 by reason of a back-fire of the engine during the cranking operation. As shown the friction which are externally splined for engagement with corresponding splines 29 cut internally of the forward portion 3| of the supporting cylin der H. The discs are held in frictional engagement between two pressure plates 33 and 34 by springs 36 and an annular member 31 which is adjustably secured to the threaded outer end 39 of member 26 and holds springs 36 in compression to the desired degree; the desired degree being preferably suchas to dissipate the entire force of the reverse rotational impulse before the parts can rotate more than a fraction of a single revolution. Pressure plate 33 rests against a shoulder 4| on member 26, and serves as an abutment for the friction disc assembly.

During normal cranking the rollers 44 of the uni-directional clutch will roll freely in their cage 45, with'out transmitting any rotational effort to the inner race 26; but if and when a back-fire occurs these rollers will wedge between the two races and transmit the reverse rotational impulse to the friction disc assembly, where it will be dissipated without damage to or interference with the resumption of normal cranking by the starter unit l2, whose jaw l1 remains meanwhile in engagement with engine jaw I8 and thereby facilitates such resumption of the cranking operation as soon as the effect of the back-fire has been absorbed in the disc assembly 25.

What I claim is:

The combination with an engine shaft, of a starter engageable therewith to turn said shaft in one direction, means including a plurality of rollers surrounding said shaft for facilitating initial rotation thereof by said starter, and constantly engaged friction means including a plurality of friction elements all of which remain stationary during normal starting of the engine, but some of which are rotatable with said rollers in a direction opposite to that in which said starter normally rotates, said friction means coacting with said rollers to resist such opposite rotation.

ROMEO M. NARDONE. 

